Antisolvent Effect of Alcohols on Sodium Salts Solubility in Glycerol-Water Mixtures

VELEZ, ALEXIS R; LAURA J. ROVETTO, ; MUFARI, ROMINA

Villa Carlos Paz

Conferencia; XI Iberoamerican Conference on Phase Equilibria and Fluid Properties for Process Design; 2018

IPQA - Instituto de investigación y desarrollo en ingeniería de Procesos y Química Aplicada

Purification processes of crude glycerol (20-60% of glycerol, methanol, water, methyl esters, free and saponified fatty acids, rests of catalyst and inorganic salts) from biodiesel industry involve different chemical and physical treatments, including an evaporation step to eliminate the excess of alcohol and water and the acidification of crude glycerol [1]. The acidification step refers to the addition of an inorganic acid to induce a phase segregation to separate matter organic non glycerol (MONG) mainly composed by free and saponified fatty acids and methyl esters. Salts are formed due to the presence of sodium or potassium catalyst. To promote the precipitation of the formed inorganic salt dissolved in the glycerol rich phase, the acidification process must be carried out in the presence of alcohol, which acts as an anti-solvent [2]. This work aimed to investigate the antisolvent effect of methnol, ethanol and isopropyl alcohol, at 303 water content on solubility of sodium chloride (NaCl) and sodium sulphate (Na2SO4) in mixtures of glycerol + water + alcohol, as model components present in the glycerol purification process.